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» Glavni naslovi






The central point of Earth is located more than 6,000 km beneath the surface, and the nearest layer of the core is approximately 3,000 km below us. The deepest hole drilled by humans at the planet’s surface is the Kola super hole at the Kola peninsula, near Murmansk in Russia – it reaches the depth of 12.3 km.
All events on Earth, known to men, take place close to its surface. Lava that comes up from the volcano melts at profundity of several hundred kilometers beneath the surface. Even diamonds, who require extremely high temperatures and pressure, are formed in rocks at the depth lesser than 500 km. Everything beneath that is shrouded in mystery and seems unfathomable. Still, surprisingly much is known about the core. There is a certain idea about the way it was formed several billions of years ago, and all with not a single physical sample. How does the core reveal its secrets?



Games with numbers

Already at the very first event “May, month of mathematics” the organizers achieved the basic objective: popularization of this science – difficult and requiring for a majority of people. This year’s, sixth traditional event, held in Belgrade, they made a step further – by including a Mathematical Show in the program. A slogan „“Mathematics, my own chance” indicated that the event would be dedicated to combinatorics, probability, statistics – in a word those mathematical areas which are evidently applied in everyday life. The international mathematical show, presented in the first week of the event, brought together seven, primarily outstanding populizers of mathematics.
The Irish mathematician, member of the national Academy of Science, writer and amateur magician, Colm Mulcahy, dedicated his lecture to Martin Gardner, mathematician, journalist advocating recreational mathematics, and also author of hundreds of serious mathematical studies. To a prevalently young audience he presented implementation of Fibonacci sequence (1,2,3,5,8,13… in which the next number in the sequence results from summing of the previous two) using a card trick where, with a little bit of skillfulness, based on the sum of the two dragged out cards, one can easily conclude which are the cards in question. From him it could be learned that the number of possible arrays of the 52 cards in a pack is 8x1067, which is more than the number of particles in a galaxy.



Small hydro power plants

Contribution of each renewable source of energy is significant even if it is measured in percentages. Such is the case of small hydro power plants; the portion of electricity they generate is, in the overall production, measured in percentages. By definition, this category concerns power plants of installed power bellow 20 MW (the upper limit in the USA and Canada stands at 50 MW, and in Serbia at 30 kW).
Advantage of small power plants is that they do not require substantial civil works and do not have significant water reservoirs before the dams, therefore, their impact on the environment and the eco- system is lesser by far. They use the energy of water courses and channels, irrigation networks, energy of ocean waves, sometimes small streams where the fall of water does not exceed 20 m. The advantage of such a power plant is that it has minor environmental impact and is, therefore, ecologically acceptable. A special type of power plan is being placed directly into the waterway, which additionally simplifies the civil works, reduces investments, does not disturb river traffic and has no impact on biosphere, while it needs to be mentioned that their power is also small, 25-50 kW.



Space probe missions

Apart from sending data on space objects of the Solar system, and thus constantly complete the human perception of our closest cosmic neighborhood, space probes could be considered as technological out-guard of mankind in places that humans will not yet reach for some long portion of time. They are special kind of technologic inventions that sometimes exceed anticipations of the earlier science fiction.
Answer to the question: what is the overall number of space probes presently performing their missions – is not a simple one and depends on a number of facts. First, it needs to be cleared what space equipment we consider to be space probes. By the way of their motion those would be devices launched out of the space in which the Earth’s gravitation field prevails, thus becoming satellites of other space objects, or, if possible, enter the atmosphere or even land on the surface of those objects, while some are in the trajectory for leaving the Solar system. Astronomic satellites located at Lagrange points Earth-Sun L1 and L2 we conditionally do not consider space probes, for their trajectories are both heliocentric and geocentric and could be treated in a twofold way



Development of life in fresh water environments

Life is presented by two extremities – its beginning and its end. In case of a single being, life develops and the creature grows, however, at the level of species, genus, family and order live evolves.
In the ancient Mesozoic oceans a huge number of animals of prey abruptly developed. In shallow water environments fishes with jaws and crabs with pincers appeared, as well as many other organisms adapted to various ways of nourishment: crashing and drilling of shells, taking the soft body out of it, etc. Organisms which were their prey responded by developing of special strategies for avoiding of the enemy. Clams with robust shells and spines developed. Some groups developed a lid of the shell (operculum). Research of fossilized remains indicates that the living world was more diversified than we can imagine, not only in the seas and oceans but also in the fresh water environments.



Smarting and Brawas

A new Belgrade-located startup company “mBrainTrain” has developed the first mobile EEG devices of premium quality the usage of which is still to move forward the boundaries of (neuro) science. “Smarting” already has more than 50 prominent users, top class research laboratories in 15 most developed countries of the world, and “Brawas” will be available to all of us – for optimization of our mental and emotional conditions, for cognitive anti-aging, for purposes that we do not yet portend… At the beginning of the last century, recording of brain waves – electroencephalography (EEG) – was one of those discoveries that marked a milestone in the history of medicine. Numerous similar revolutionary medical innovations had to wait till the end of the 20th century and the era of computer technology in order to have their full practical usage feasible, or more efficient.



Lyme disease

Bacterial infection transmitted by infected ticks can cause in a human being a serious multisystem disease. However, if discovered at an early stage, it can be completely cured with antibiotics. We live in a geographic area where with every stay outdoors we are exposed to the risk of contact with these tiny parasites. Therefore, we need to take this into consideration, warns Boško Misita, pharmacist and medical biochemist of Bel Medic, Belgrade.
Who would even think that we could be exposed to some serious danger while walking cozily in a city park or in a private garden? Lyme diseases, for which there is no vaccine, warnings about its transmitter, the tick, as the most dangerous “beast” of the quiet forests, parks and meadows, should not be taken as a joke. This tiny, seemingly harmless ectoparasite, of the class of Arachnida, is active from late spring till early autumn, and in that period, as a potential transmitter of the Lyme borreliosis, can be dangerous for human health



Ultrasound in urology

Ultrasound checkup is one of the initial health checks in the diagnostic algorithms because it is low cost, efficient and with no exposure to ion rays. In some cases it is sufficient for setting of an exact diagnose. Ultrasound diagnostics, or ultrasonography, has an important role in assessment of the urinary tract. As in other areas of medicine, in urology, which has relied on ultrasonography for more than three decades, the ultrasound is one of the initial radiological checkups, because of its availability, lower cost and complete harmlessness – there is no exposure to ion rays.
Apart from that, the checkup does not require usage of contrast agents which can cause allergic reactions with some persons, and no particular preparation of the patient is needed. Dr. Zoran Radosavljević, urology specialist and ultrasound subspecialist in the Belgrade located General hospital Bel Medic, adds that urological ultrasonography is a very quick and efficient method which in the shortest period of time can provide data not only on the diagnostic path that should potentially be taken as the next step, but often also the data based on which the final diagnosis can be made.


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